LMH6643MMX Equivalent & Substitute Parts

Part Overview

The LMH6643MMX is a voltage feedback operational amplifier featuring dual circuits in an 8-VSSOP surface mount package, manufactured by Texas Instruments. This device is classified as obsolete, which necessitates identification of active equivalent and substitute components for new designs and production continuity. The LMH6643MMX delivers rail-to-rail output capability with a slew rate of 135V/µs and -3dB bandwidth of 130 MHz, suitable for applications requiring moderate-speed signal conditioning and amplification in compact form factors.

Key Parameters

Parameter	Value	Unit
Amplifier Type	Voltage Feedback	—
Number of Circuits	2	—
Output Type	Rail-to-Rail	—
Slew Rate	135	V/µs
-3dB Bandwidth	130	MHz
Current - Input Bias	1.6	µA
Voltage - Input Offset	1	mV
Current - Supply (per channel)	2.7	mA
Current - Output / Channel	75	mA
Voltage - Supply Span (Min)	2.7	V
Voltage - Supply Span (Max)	12.8	V
Operating Temperature	-40 to 85	°C
Package / Case	8-TSSOP, 8-MSOP (0.118", 3.00mm Width)	—
Mounting Type	Surface Mount	—
RoHS Status	RoHS non-compliant	—

Substitute Part Grouping Explanation

Substitution of the LMH6643MMX is determined by the following critical parameters: dual-circuit configuration, voltage feedback amplifier topology, rail-to-rail output capability, surface mount 8-pin package compatibility, and operating supply voltage range of 2.7V to 12.8V. Substitute parts must maintain these core electrical and mechanical characteristics to ensure functional equivalence in existing circuit designs.

The substitute parts are grouped into two categories:

Category 1: Direct Functional Equivalents (Texas Instruments LMH6643 Series) LMH6643MMX/NOPB is the active production variant of the same base product number (LMH6643), offering identical electrical specifications and package footprint. This part differs only in product status (active vs. obsolete) and RoHS compliance.

Category 2: Cross-Manufacturer Alternatives (Analog Devices and Maxim Integrated) LT6206 series (Analog Devices) and MAX4017/MAX4217 series (Maxim Integrated) provide voltage feedback amplifier functionality with dual circuits and rail-to-rail output in compatible 8-pin surface mount packages. These alternatives exhibit higher slew rates (600V/µs) and different bandwidth characteristics, but maintain compatibility with the supply voltage range and package footprint of the original device.

Parameter Comparison

Part Number	Manufacturer	Amplifier Type	Circuits	Output Type	Slew Rate (V/µs)	-3dB BW (MHz)	Supply Min (V)	Supply Max (V)	Package	Product Status	RoHS
LMH6643MMX	Texas Instruments	Voltage Feedback	2	Rail-to-Rail	135	130	2.7	12.8	8-VSSOP	Obsolete	Non-compliant
LMH6643MMX/NOPB	Texas Instruments	Voltage Feedback	2	Rail-to-Rail	135	130	2.7	12.8	8-VSSOP	Active	ROHS3 Compliant
LT6206CMS8#PBF	Analog Devices Inc.	Voltage Feedback	2	Rail-to-Rail	600	—	2.7	12.6	8-MSOP	Active	ROHS3 Compliant
LT6206CMS8#TRPBF	Analog Devices Inc.	Voltage Feedback	2	Rail-to-Rail	600	—	2.7	12.6	8-MSOP	Active	ROHS3 Compliant
LT6206IMS8#PBF	Analog Devices Inc.	Voltage Feedback	2	Rail-to-Rail	600	—	2.7	12.6	8-MSOP	Active	ROHS3 Compliant
LT6206IMS8#TRPBF	Analog Devices Inc.	Voltage Feedback	2	Rail-to-Rail	600	—	2.7	12.6	8-MSOP	Active	ROHS3 Compliant
MAX4017EUA+	Analog Devices Inc./Maxim Integrated	Buffer, Voltage Feedback	2	Rail-to-Rail	600	200	3.15	11	8-uMAX/uSOP	Active	ROHS3 Compliant
MAX4017EUA+T	Analog Devices Inc./Maxim Integrated	Buffer, Voltage Feedback	2	Rail-to-Rail	600	200	3.15	11	8-uMAX/uSOP	Active	ROHS3 Compliant
MAX4217EUA+	Analog Devices Inc./Maxim Integrated	Buffer, Voltage Feedback	2	Rail-to-Rail	600	230	3.15	11	8-uMAX/uSOP	Active	ROHS3 Compliant
MAX4217EUA+T	Analog Devices Inc./Maxim Integrated	Buffer, Voltage Feedback	2	Rail-to-Rail	600	230	3.15	11	8-uMAX/uSOP	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: LMH6643MMX/NOPB

For applications currently using the obsolete LMH6643MMX, the LMH6643MMX/NOPB is the direct replacement. This part maintains identical electrical performance, package footprint, and pinout while offering active product status and ROHS3 compliance. No circuit redesign is required. Inventory availability is significantly higher (52,578 units) compared to the obsolete variant.

Secondary Recommendations: LT6206 Series (Analog Devices)

The LT6206CMS8#PBF, LT6206CMS8#TRPBF, LT6206IMS8#PBF, and LT6206IMS8#TRPBF are suitable alternatives for applications where higher slew rate performance (600V/µs vs. 135V/µs) is beneficial or acceptable. These parts maintain the dual-circuit voltage feedback topology, rail-to-rail output, and compatible supply voltage range. The 8-MSOP package is mechanically compatible with the original 8-VSSOP footprint. All variants are active products with ROHS3 compliance. Selection between tube (PBF) and tape & reel (TRPBF) packaging depends on procurement and assembly requirements.

Tertiary Recommendations: MAX4017 and MAX4217 Series (Maxim Integrated)

The MAX4017EUA+, MAX4017EUA+T, MAX4217EUA+, and MAX4217EUA+T provide higher bandwidth performance (200 MHz and 230 MHz respectively) with 600V/µs slew rate. These parts are classified as buffer amplifiers with voltage feedback topology. The minimum supply voltage is 3.15V, which is higher than the LMH6643MMX specification of 2.7V. Applications operating at supply voltages below 3.15V are not compatible with these alternatives. All variants are active products with ROHS3 compliance.

Compliance Considerations

The original LMH6643MMX is RoHS non-compliant. All recommended substitutes (LMH6643MMX/NOPB, LT6206 series, and MAX4017/MAX4217 series) are ROHS3 compliant, meeting current environmental and regulatory requirements for electronic component manufacturing and assembly.

Frequently Asked Questions (FAQ)

Q1: Can LMH6643MMX/NOPB be used as a direct drop-in replacement for LMH6643MMX?

Yes. LMH6643MMX/NOPB is the active production variant of the same base product (LMH6643). Electrical specifications, pinout, and package footprint are identical. The only differences are product status (active vs. obsolete) and RoHS compliance (ROHS3 vs. non-compliant). No circuit modifications are required.

Q2: What are the key differences between LMH6643MMX and LT6206 series?

Both are dual-circuit voltage feedback amplifiers with rail-to-rail output in compatible 8-pin surface mount packages. The LT6206 series exhibits a significantly higher slew rate (600V/µs vs. 135V/µs). The LMH6643MMX supports a minimum supply voltage of 2.7V, while the LT6206 series minimum is also 2.7V. The maximum supply voltage for LT6206 is 12.6V compared to 12.8V for LMH6643MMX. These differences are within acceptable tolerance for most applications.

Q3: Are MAX4017 and MAX4217 suitable replacements for low-voltage applications?

The MAX4017 and MAX4217 series have a minimum supply voltage specification of 3.15V. Applications requiring operation at 2.7V (the minimum for LMH6643MMX) are not compatible with these alternatives. Verify your circuit's minimum supply voltage requirement before selecting MAX4017 or MAX4217 variants.

Q4: What is the difference between tube and tape & reel packaging options?

Tube packaging (PBF suffix) is suitable for manual assembly and small-quantity procurement. Tape & reel packaging (TRPBF or +T suffix) is designed for automated pick-and-place assembly and high-volume production. Both packaging formats contain identical components; the selection depends on assembly methodology and procurement volume requirements.

Q5: Can I use LT6206 or MAX4017/MAX4217 in existing PCB designs without layout modifications?

The LT6206 series uses 8-MSOP package, and MAX4017/MAX4217 use 8-uMAX/uSOP package. Both are mechanically compatible with the original 8-VSSOP footprint in terms of pin spacing and overall dimensions. However, verify PCB land pattern compatibility with your specific design. Pinout must be confirmed to ensure correct signal routing.

Q6: Which substitute part offers the best performance upgrade?

The MAX4217EUA+ and MAX4217EUA+T offer the highest -3dB bandwidth (230 MHz) and slew rate (600V/µs) among all alternatives. However, the minimum supply voltage requirement of 3.15V may limit applicability. For applications requiring higher performance within the original 2.7V minimum supply specification, the LT6206 series is the appropriate choice.

Q7: Are all substitute parts RoHS compliant?

Yes. All recommended substitute parts (LMH6643MMX/NOPB, LT6206 series, MAX4017 series, and MAX4217 series) are ROHS3 compliant. The original LMH6643MMX is RoHS non-compliant. Compliance with current environmental regulations is achieved through any of the recommended substitutes.

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